More than 600 people endured rain and cold on Sunday to rally against Friday's airstrike in the town of Samarbagh, about 50km east of Damadola.
The airstrike killed 18 people, described by villagers as innocent civilians.
Protesters chanted "Death to America", "Death to Bush", and "A friend of America is a traitor", while also denouncing General Pervez Musharraf, the Pakistani presidentfor co-operating with the United States.
A rally speaker said Washington was targeting Pakistan because of its nuclear weapons.
"Pakistan is a nuclear power, and America has tightened the siege against it," said Aizaz-ul Mulk Afkari, a leader from Hezb-ul Mujahidin group.
A coalition of anti-US Islamic groups planned more protests elsewhere later in the day. The previous day, about 8000 tribesmen staged a rally in the town of Inayat Qala, and a mob set fire to the office of a US-backed aid agency in a nearby village.
Thousands have joined protests
President Musharraf, meanwhile, warned his countrymen not to harbour militants, saying it would only increase violence within Pakistan's borders.
"If we kept sheltering foreign terrorists here ... our future will not be good," Musharraf said in a speech broadcast on Sunday by state-run Pakistan Television.
But his government has protested to the US Embassy amid growing frustration over a recent series of suspected US attacks along the frontier, apparently directed at Islamic fighters.
Pakistani officials said earlier indications from US intelligence sources that al-Zawahiri might have died in Friday's missile raid were "not true".
Tensions remained high on Sunday near the village of Damadola, the site of the attack in the Bajur tribal area on the Afghan border, after police tear-gassed thousands of protesters who torched a US-funded aid agency office on Saturday.
Aljazeera's Pakistan bureau chief Ahmed Zaidan reported that thousands of people demonstrated in the area against the US air strike on Saturday.
An estimated 5000 people had gathered at a stadium near Khar, the main town in the Bajur tribal zone.
Some demonstrators on Saturday set fire to the offices of Associated Development Construction, a non-governmental organisation funded by the US Agency for International Development, an official at the aid group said.
"The US cannot do this without Pakistan's support. We are leaving it to God to give us justice"
father of three children
killed in the raid
Zaidan said Pakistani Muslim organisations had called for protests on Sunday against the US presence and violations in the country.
Earlier, CNN had quoted sources saying the CIA ordered Friday's strike after receiving intelligence information that al-Zawahiri was in a village near the border.
ABC News quoted Pakistani military sources as saying that five of those killed were "high-level" al-Qaida figures.
But tribesmen in Damadola village in the Bajur tribal area said only locals were killed - 18 of their kinfolk, including eight women and five children.
"We are the victims of infidel forces and God will destroy the infidels," wept 70-year-old villager Mohammad Rahim Khan, whose three grandchildren were killed in one of the three blasts reported by residents.
"The US cannot do this without Pakistan's support. We are leaving it to God to give us justice," said the children's father, 35-year-old Mohammed Khan.
The strike was said to be carried
out by drones (file)
Although the toll and the identities of the dead have not yet been established, local residents said five women and five children were among the dead and that all were tribespeople.
Pakiistan's Foreign Ministry said it had summoned Ryan Crocker, the US ambassador, on Saturday and handed over a formal protest about the incident.
"According to preliminary investigations there was foreign presence in the area and that in all probability was targeted from across the border in Afghanistan," a ministry statement said.
Shaikh Rashid Ahmed, the information minister, said: "We want to assure the people we will not allow such an incident to reoccur," reading a statement which termed the attack as "highly condemnable".
The FBI anticipates performing DNA tests on the victims, a law enforcement official said on Saturday.
In Washington, Pentagon, State Department, National Security Council and intelligence officials did not immediately provide additional details about the attack.
"The US ambassador will be called to the foreign office... We want to assure the people we will not allow such an incident to reoccur"
Shaikh Rashid Ahmed,
DNA tests to determine the victims' identities are expected to be conducted in the US, according to the law enforcement official who spoke on condition of anonymity because a formal request for such testing had not been made public.
A Pakistani intelligence source said he had been told by US officials the strike was ordered based on information that al-Zawahiri and Mullah Mohammad Omar, the toppled Taliban leader, had been invited to a dinner to celebrate this week's Muslim Eid al-Adha festival.
They had no confirmation, however, that either had been there at the time of the attack at about 3am on Friday (2200 GMT on Thursday).
Mullah Dadullah, a senior Taliban commander, said no Taliban commander had been at the dinner.
On the other hand, Major Chris Karns, a spokesman at US Central Command in Florida, the command responsible for the region, said there had been no official report of an attack in Pakistan.
Tribesmen stand by their home
damaged by Friday's air raid
Incidentally, unidentified Pakistani officials have been quoted in news reports as saying that up to 11 extremists are believed to be among the dead.
One Damadola resident said three or four foreigners had come from Afghanistan for Eid.
Another said he had seen bodies of at least two people who seemed to have been outsiders.
"Where these bodies have gone, I don't know," he said.
Pakistan's The News newspaper said the villagers had been buried after a mass funeral led by Maulana Faqir Muhammad, a cleric wanted for giving shelter to suspected al-Qaida members.